This research project has addressed itself to a number of facets related to chromosome changes in bladder cancer. A major aim of the project was to define chromosomal changes in papillary (noninvasive) bladder tumors, with the hope of establishing parameters useful in predicting recurrence. To a large extent, this was accomplished through the demonstration that the presence of abnormal chromosomes (markers) results in more than 90 percent chance of recurrence of such tumors, whereas the absence of such markers has the opposite indication. More recently, we have been engaged in the development of a method for analyzing metaphases in bladder cancer so that the yield of such metaphases would be higher than usually obtained with presently available methods, result in preparations which are more suitable for banding and, thus, for more detailed analysis of some of the more complicated changes and the ability to determine the chromosome constitution on small pieces of tissue. This we think we have accomplished by utilizing collagenase II or IV and DNase I in disaggregating cells, followed by short-term incubation. At present, we are analyzing as many of bladder cancers as become available with the hope of ascertaining nonrandom changes, as well as correlating the karyotypic findings with the clinical, therapeutic and prognostic parameters of the cases. A study which addressed itself to centromeric heterochromatin polymorphism has about been completed and indicates that there appears to be no significant differences between the incidence of such polymorphism in the cells of patients with bladder cancer as compared to a control population of subjects without a history of cancer and 85 years old or older. These findings are of importance, since a number of laboratories have indicated a higher susceptibility to bladder cancer as indicated by a higher incidence of polymorphism in patients with this malignancy. Thus, more studies of a more refined nature will have to be undertaken in order to settle this issue. Pilot studies are being performed in which bladder tumor samples are shipped to Buffalo for karyotypic analysis in order to ascertain the feasibility of undertaking such a study nationwide.